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Uzik M.,PPRC Piestany Plant Production Research Institute Piestany | Zofajova A.,PPRC Piestany Plant Production Research Institute Piestany
Cereal Research Communications

Ten winter wheat cultivars released in the years 1921-2003 in Slovakia were evaluated in pot experiment in 4 variants of N fertilization and in 2 terms of harvest (heading-a, maturity-m). Biomass N concentration at heading, grain N concentration (Ng), straw N concentration (Nv), and biomass N concentration at maturity were determined. N uptake and characteristics of N translocation, accumulation in grain and utilization were estimated. The year of cultivar release (YCR) was in relationships with nitrogen translocation efficiency (NTRE) (r = 0.720++) and with decreasing N% in vegetative biomass during grain filling (RNT) (r =-0.614). Strong correlation between YCR and N uptake in grain (r = 0.796), YCR and N harvest index (NHI) (r = 0.816++), and YCR and N utilization for grain (NUTg) (r = 0.877++) indicated that the modern cultivars more intensive accumulated N in grain and utilised N for grain than old ones. YCR was in negative correlation with N uptake in biomass at heading (r =-0.790++), N utilization for biomass (r =-0.678+) and with ratio Ng to Nv (relative N accumulation RNA) (r =-0.710+). Modern cultivars, in spite of their higher grain N uptake (NUP), lower N concentration in straw, higher N accumulation in grain (NHI) and higher efficiency of N translocation (NTRE) and (RNT), had lower N grain concentration than old cultivars. At the same or lower total N uptake they had considerably higher grain yield and therefore between Ng and NUTg was strong negative correlation (r =-0.977++). This is a result of the unilateral selection on grain yield. Selection should be concentrated not only on increasing of N uptake efficiency, but also on increasing of total N uptake by increasing of biomass N concentration. RNT and RNA are also recommended for selection on increasing of N grain concentration. Hypothetic models of cultivars with different NUP, NUTg and different relationships between NUTg and Ng were discussed. Source

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